Hypoxic-ischemic encephalopathy (HIE) represents a serious problem in newborns, occurring in 3-9 of every 1,000 term infants, with about half of these HIE babies dying or suffering life-long severe handicaps, such as mental retardation or cerebral palsy. Current efforts to reduce the effects of HIE by hypothermia (cooling) have been hampered by the lack of a reliable noninvasive method of monitoring the infant's brain temperature during the hypothermic treatment, which lasts about 48 hours. The primary objective of this Phase I feasibility study was to evaluate Passive Microwave Radiometry (PMR) for monitoring intracranial temperature in neonates. The Phase I program has been successfully completed. The significant challenge of the overall program occurs in Phase II involving the integration of the radiometric receivers into the transducers and developing the logic and circuitry required to combine the two radiometric outputs to determine temperature at depth. The goal of the Phase II program is to develop an affordable system for the reliable and continuous monitoring of intracranial temperature in neonates. 7. Project Narrative Two to four of every 1000 babies delivered in the United States experience an obstetrical complication resulting in asphyxial injury to the brain leading to the development of cerebral palsy, mental retardation or even death. Recent clinical studies have shown that hypothermia decreases the injured brain's metabolism and oxygen requirements, and can significantly decrease the chances of physical disability and death. Although promising, hypothermia is an evolving therapy and there is much to learn regarding the optimal degree and duration of hypothermia. Knowledge of exact brain temperature is needed before these important questions can be adequately answered. [unreadable] [unreadable] [unreadable]